'True' Digital Coater Could Make Big Impact

Variable digital coating may not have been on the finishing radar for many people. But PAT Technology Systems has been working on it for more than 24 months. The Montreal-based company, which primarily supplies air purifiers to keep the insides of platesetters clean, appeared at Labelexpo in Chicago last month to show Rotoworx—a roll-fed converting and digital UV coating system capable of variably placed coating and single-color, variable-data printing.

At Graph Expo, the firm is introducing Varstar, which incorporates some of the same technology in a sheetfed digital coater being displayed alongside the Rotoworx (Booth No. 667).

Coaters integrated to digital finishers have been in development for the past two years—with inline, nearline and offline offerings presented. These are critical components to allow toner-based digital print devices to successfully produce mailers that can sustain the rigors of the postal stream.

So far, coaters have used dry toner overlays or rollers to flood-coat digital print. Varstar and Rotoworx use inkjet technology based on Xaar's piezo electric head with Hybrid Side-Shooter (HSS). This novel application is capable of dropping flood or spot coating onto sheets, matching placement to the same image file driving the digital print engine—or even a conventional platesetter.

PAT distinguishes its “true” digital coating device from coaters that use analog processes to coat digital printing. In fact, it has engineered the system to be capable of rendering variable gloss levels using a single fluid: the proprietary Nuvo coating.

The Varstar unit takes incoming sheets on a feeder tray and establishes register against the leading paper edge. Sensors adjust the fit to the paper size. Sheets are stacked at a 45° angle at the infeed, which sizes itself automatically. Suction cups pull the sheet upward, placing it onto a round steel vacuum drum that holds it tightly as it passes under the inkjet bar and is coated, then UV-cured.

Varstar handles a maximum 14.4×22.5´´ sheet and is rated at speeds of 8,000 sph—more than adequate for the output of a Xerox iGen3. Register can be electronically controlled circumferentially and laterally to +/-150 microns. It is capable of full-bleed coating, as well as tight-registration spot coating. The JDF- and PDF-compatible device can be fitted with an optional second bar for printing variable data—so offset printed sheets may be personalized and coated.

Special effects, such as matte and gloss combinations, are possible, holding the sheet for repeat passage under the coating and curing bars.

“We're bringing coating into the digital age,” says Jamie Koehler, PAT's head of product development. Jean Maurice Fournier, president of the nearby Imprimerie St-Julie plant, which has three HP Indigo presses, says, “This technology can save time, money and add value to the print jobs.”

In addition to protecting digital print production, it offers creative applications: a contour effect on globes can be enhanced with shaded coating, for example; or a dry-back gloss/matte effect can be executed with the system, using the proprietary software that controls the system. www.pattechnology.com